Acne is an inflammatory dermatological disorder, which occurs frequently in adolescence and with some regularity in older adults of the human species. The condition of acne can include skin lesions ranging from the comedo in a pilosebaceous follicle, to more severe como-inflammatory symptoms such as pustules, papules, cysts and nodules. The condition is not only uncomfortable for the victim, but also embarrassing, and can result in disfigurement and scarring.
The pathology of acne vulgaris is believed to involve a number of actors: the first of which is the formation of comedones more commonly referred to as whiteheads (closed comedones) and blackheads (open comedones). These are solid horny masses that plug follicles and are associated with increased production of sebum. They are made up of tightly packed keratinized cells and sebum. As the comedo enlarges through continued accumulation of keratinized cells, pressure builds up within the follicles which eventually rupture, dumping the contents consisting of horny material, sebum and bacteria into the skin. This provokes inflammatory responses which take the form of pustules (pimples) when the rupture is small and cystic-nodules with complete rupture.
Many different approaches to ameliorating this disorder have been attempted in the past, with some treatments more effective than others. Attacks ranging from simple washing and cleansing to pharmaceuticals have been employed. One group of agents used in acne treatment include the retinoids and retinols. While these agents can significantly improve acne, their undesirable side effects range from mild to severe irritation, redness, peeling, and itching and burning sensation. Thus, it is desired to have a single topical treatment that could prevent or reverse acne with minimal or no undesired side effects.
Aging of the skin is a complex phenomenon resulting from the interaction of several intrinsic and extrinsic factors. Skin changes associated with aging often manifest as cosmetic disabilities. Due to its psychological impact, aging of the skin has become an issue of great social significance and concern. With baby boomers aging, the era of cosmetic care, cosmetic maintenance and rejuvenation gains increased awareness. Methods for preventing and treating skin aging are highly desired. Intrinsic aging is an inevitable, genetically programmed process. Among extrinsic influences (wind, heat, cigarette smoke, chemicals, etc.), ultraviolet radiation appears to be the single most important factor associated with aging of the skin. Photoaging is induced by cumulative exposure to ultraviolet radiation (UVR). Increased recreational sun exposure, including excessive sunbathing, the depletion of stratospheric ozone, and the use of UVR in the treatment of various skin diseases, have led to increased prevalence of photoaging during the last decades. Photodamage can be prevented by sun avoidance and proper sun protection, and could be reversed by the use of topical retinoids, which could be irritating and expensive. Overexposure to ultraviolet and visible radiation also causes sunburn. The use of aspirin and other nonsteroidal anti-inflammatory drugs, cool baths and topical steroids offer only mild relief.
Various approaches to treating acne, photodamage and other skin conditions have been attempted in the past, including treatment with Vitamin A acid (also known as “tretinoin”) and natural retinoids or retinoid precursors such as Vitamin A alcohol (also known as “retinol”). (See U.S. Pat. No. 4,877,805 and U.S. Pat. No. 4,355,028, for example). However, topical treatment with retinoids can be very irritating to the skin and uncomfortable for the patient. It can cause redness, which may be embarrassing to the patient, particularly those suffering from acne in their teenage years. Oral treatment with retinoids has been found to have teratogenic effects.
Thus, it would be desirable to find a topical treatment for acne, rosacea, photodamage and other skin conditions that does not cause redness to the skin.